Steerable ultrasound attachment for endoscope

ABSTRACT

An endoscope add-on assembly adapted to be attached to a target endoscope. The assembly includes an ultrasound imaging sub-assembly, including a communications cable connected to an ultrasound imaging head and an imaging head movement sub-assembly, including a conduit, holding a tension member that is attached to the ultrasound imaging head. Further included are connective elements, adapted to permit the endoscope add-on assembly to be attached to the target endoscope. Finally, the imaging head movement sub-assembly is detachable from the ultrasound imaging sub-assembly, thereby permitting the imaging head movement subassembly to be processed separately from the ultrasound imaging sub-assembly, after use.

RELATED APPLICATIONS

This application is a continuation of application U.S. Ser. No.16/523,971, filed Jul. 26, 2019, which itself is a continuation-in-partof PCT international application PCT/US19/27331, filed Apr. 12, 2019,which itself is a continuation of U.S. application Ser. No. 15/951,347filed Apr. 12, 2018, now U.S. Pat. No. 10,363,014, issued Jul. 30, 2019,all of which are incorporated by reference as if fully set forth herein.

BACKGROUND 1. Field of the Invention

The Invention is in the field of ultrasound imaging add-on equipment forendoscopes.

2. Background Art

Endoscopic ultrasound has undergone a rapid pace of development, nowbeing used for the diagnosis and treatment of a wide variety of medicalproblems. As an endoscope can reach a location in the intestinal tract,closer than any skin surface, there is an opportunity to image from acloser location, and to obtain a tissue sample, using a biopsy needleand implement a variety of treatments. But due to an expense of greaterthan $300,000 for a complete system, endoscopic ultrasound systems aregenerally restricted to major hospitals. Endoscopes, however, are usedin physicians' offices, most outpatient surgery centers and virtuallyall hospitals.

One type of endoscope is an upper endoscope, used to image and taketissue specimens from the upper GI tract. In this type of endoscope, ifa needle is used to collect a specimen, it is typically advancedstraight out of an endoscope lumen in a distal direction. Other types ofendoscopes are bronchoscopes for viewing air passageways in the lungsand colonoscopes for viewing the colon.

Yet another type of endoscope is a duodenoscope, designed to beintroduced into the duodenum (the upper part of the small intestines),and typically used to perform endoscope retrogradecholangiopancreatography (ERCP), in which the ducts of the pancreas andliver are imaged. Duodenoscopes are also used to gather tissue biopsiesfrom sites in the duodenum, including the bile ducts. Duodenoscopestypically have a tip that houses a light, a video camera, and aninstrument guide that can be tilted by an operator to control the angleat which the instrument (needle or other type of instrument) advances.Although the video camera and light can produce imagery that may helpthe endoscopist visualize potential targets directly, ultrasoundimagery, when available, provides a different, dramatically expandedview of the regional anatomy. An ultrasound add-on for endoscopes hasbeen described, but its capabilities are limited in that the viewingangle of the imaging head cannot be adjusted, and it does not providefor tissue sampling.

A problem faced by practitioners in the field of endoscopy is thethorough disinfection of the endoscope, between uses. As manyendoscopes, in particular duodenoscopes, have some mechanicalcomplexity, introducing a sterilizing material into the small spacesdefined by these mechanisms, creates a huge challenge. Recently, anendoscope mechanism, having an instrument angle adjustment mechanismthat is removable and disposable has been introduced, addressing many ofthese issues.

SUMMARY

In a first separate aspect, the present invention may take the form ofan ultrasonic endoscope assembly, having an endoscope defining one ormore lumens, and a needle that can be pushed forward out of a lumen, tocollect a biopsy specimen. An ultrasound sub-assembly is attached to theendoscope and includes a communications cable, including a set of signalpathways, and having a distal end and an ultrasound imaging headconnected to the distal end of the cable. Also, included is an imaginghead movement sub-assembly, including a conduit that is releasablyconnected to the endoscope. The conduit contains a tension member thatis releasably connected to the imaging head. Accordingly, the imaginghead movement sub-assembly can be released from the endoscope and theimaging head, to be processed separately, after use.

In a second separate aspect, the present invention may take the form ofan endoscope add-on assembly adapted to be attached to a targetendoscope. The assembly includes an ultrasound imaging sub-assembly,including a communications cable connected to an ultrasound imaging headand an imaging head movement sub-assembly, including a conduit, holdinga tension member that is attached to the ultrasound imaging head.Further included are connective elements, adapted to permit theendoscope add-on assembly to be attached to the target endoscope.Finally, the imaging head movement sub-assembly is detachable from theultrasound imaging sub-assembly, thereby permitting the imaging headmovement subassembly to be processed separately from the ultrasoundimaging sub-assembly, after use.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are illustrated in referenced drawings. It isintended that the embodiments and figures disclosed herein are to beconsidered illustrative rather than restrictive.

FIG. 1 is an isometric view of an imaging assembly having an endoscopeand an ultrasound imaging assembly added on, according to a preferredembodiment of the present invention.

FIG. 2 is an isometric view of the distal end of the assembly of FIG. 1.

FIG. 3 is a side view of the distal end of the assembly of FIG. 1 , in afirst position.

FIG. 4 is a side view of the distal end of the assembly of FIG. 1 , in asecond position.

FIG. 5 is a side view of the distal end of an alternative embodiment ofan imaging assembly.

FIG. 6 is a side view of another alternative embodiment of an imagingassembly.

FIG. 7 is an alternative embodiment of an imaging assembly, having anultrasound imaging sub-assembly that includes an ultrasound headmovement assembly that is detachable, and showing three alternativeneedle guides.

FIG. 8 is a sectional view of a of the assembly of FIG. 7 , showing aneedle guide in a deployed state.

FIG. 9 is a detail view of a portion of the assembly of FIG. 7 , showingtwo of the parts disassembled from each other.

FIG. 10 is the detail view of FIG. 9 but showing the two parts joined.

FIG. 11 is a sectional view taken along line 11-11, of FIG. 10 .

FIG. 12 is a sectional view taken along line 12-12 of FIG. 10 .

FIG. 13 is a sectional view of the tip of the assembly of FIG. 7 ,showing the needle guide used to guide a needle.

FIG. 14 is a sectional partial view of the assembly of FIG. 7 having adifferent style of needle guide.

FIG. 15 is a view of the assembly of FIG. 14 , showing the needle guidein use.

FIG. 16 is an isometric view of a duodenoscope assembly, having anultrasound imaging sub-assembly.

FIG. 17 is an isometric view of the assembly of FIG. 16 , in adisassembled state.

FIG. 18 is a sectional view of the assembly of FIG. 16 , showing adifferent position for a portion of the assembly, in dashed line.

FIG. 19 is an isometric view of an alternative embodiment of aduodenoscope assembly.

FIG. 20 is an isometric of the assembly of FIG. 19 , in a disassembledstate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Definition

As used in this application, the term “endoscope” refers to anilluminated optical, typically a slender and tubular instrument used tolook deep into the body and used in procedures referred to as“endoscopy”. This term encompasses, but is not limited to upperendoscopes, duodenoscopes, colonoscopes and bronchoscopes, as well asdevices referenced simply as “endoscopes”.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In a first preferred embodiment, an imaging assembly 10 includes anupper endoscope 12 and an ultrasound assembly 14 that has been attachedto endoscope 12 by means of retaining element 18, integral to ultrasoundassembly 14. In an alternative preferred embodiment, a retaining elementis provided that is separate from ultrasound assembly 14 but workscooperatively to retain assembly 14 on endoscope 12. Assembly 14 alsoincludes an ultrasound imaging (also referred to as “transducer”) head20 that is electrically connected to a multiple signal pathway cable 22by way of a flex circuit 50 (which is also a form of a signal pathwaycable), that includes a set of parallel electrical leads, which may betraces. Cable 22, which has a multiplicity of signal pathways extendingtherethrough terminates in a connector 24, adapted to connect to animaging station. Elements 16, which may be rubber bands, or some otherform of elastic bands or clips, help to retain cable 22, to the side ofendoscope 12. A tension member 30, such as a wire (which may also havesome compressive strength) is attached to a fixation point 32 onultrasound imaging head 20 and extends through a lumen 34 (FIG. 2 ) toemerge outside of a port 36 on the proximal end of endoscope 12, to bemanipulated. In embodiments, tension member 30, does not extend throughlumen 34, but extends along the side of endoscope 12, and in someembodiments is retained by elements 16, which are modified from thesimple shapes shown in FIG. 1 , to include eyelets, to create a guidepath for tension member 30. In one embodiment, tension member 30 isconnected to controls on the proximal end of endoscope 12, to facilitatemanipulation. In embodiments, these controls may take the form of aspool, that can be easily let out, or drawn in. Endoscope 12 also isequipped with intrinsic controls for deflecting the tip of the insertiontube, to facilitate introduction to a site of interest.

In an alternative embodiment, tension member 30 is replaced by a tensionmember extending along the exterior of the endoscope, to a fixationpoint on the end of the endoscope. A physician may exert traction orpulsion on tension member 30 in any one of a variety of ways, to causeultrasound imaging head 20 to bend forward or back toward retainingelement 18, as permitted by a resiliently flexible neck 38 (FIG. 2 ). Inone method a rotatable element is used to draw in tension member 30 orpush it out.

In preferred embodiment endoscope 12 includes an element at its distalend to guide the alignment of the retaining element 18. For example,endoscope 12 many include a groove at its distal end, into which a keyelement on retaining element 18 engages. In another embodiment, anorientation guide includes a peg that fits into the lumen 34 and is usedto guide the correct orientation of retaining element 18. In oneembodiment, assembly 14 is made for intended disposal, after a singleuse, and is used in this manner. In another embodiment, assembly 14 isconstructed so as to be prepared and/or cleaned appropriately for reuse,after use, and then reused. Although until recently generallydisinfection procedures were deemed adequate, the detection of instancesof the spread of infection through endoscope has given rise to the useof high-end disinfection techniques for endoscopes. These disinfectiontechniques make use of chemicals to kill any pathogens left on the scopeafter use. Other disinfection or sterilization techniques may be used,including processing using of UV light and/or a gas, such as ozone. Inthe context of this application, the term “cleaning” encompasses alldisinfection and sterilization techniques. Generally, the materials usedin endoscopes are such that autoclaving an endoscope, or an attachmentthereto is not feasible.

Referring to FIGS. 3 and 4 , a flex circuit 50, which passes through theflexible neck 38, electrically connects imaging head 20 to cable 22.Flex circuit 50 has an electrical lead for each transducer element in anultrasound element array 52, resident in the ultrasound imaging head 20,to drive ultrasound element array 52 and relay signals from it. Array 52is covered with a protective coating 53 (FIGS. 5 and 6 ). In analternative preferred embodiment, flex circuit 50 extends from imaginghead 20 to (or through) connector 24, may define a plurality of coaxcables and may directly contact the elements of the ultrasound array 52.In another alternative embodiment, cable 22 comprises a set of coaxcable bound together with an adherent and protective substance, such asa polymer, and extends from connector 24 to imaging head 20. In yetanother embodiment, a fiber optic cable is used in place of cable 22,with light to electric convertors at its distal end. In any one of thesearrangements elements 22 and 50 could be termed separately or incombination as a multiple signal pathway cable.

In a preferred embodiment, a biopsy needle 60 (FIGS. 5 and 6 ), whichforms the sharpened, distal portion of a long, flexible, hollow-corewire, is provided. This wire is sheathed in a flexible conduit (notshown), thin enough to extend through the lumen 34 and protectingendoscope 12 from being damaged by needle 60. Once the conduit reachesthe distal end of endoscope 12, it may be pushed out to extend fromlumen 34, and provide further guidance for needle 60, which is pushedout of the conduit at a point distal to the end of endoscope 12.Alternatively, the conduit may be pushed roughly to the end of lumen 34,with the needle 60 pushed out of the conduit at that point.

Referring to FIG. 5 , in an alternative preferred embodiment tensionmember 30 extends through a channel 33 in retaining element 18 to reachfixation point 32. This figure also shows a needle 60 that has beenpushed through a lumen of the endoscope 12 and is emerging from thedistal end of the lumen. An aperture 40 is defined in neck 38,corresponding to an aperture in flex circuit 50, aligned with aperture40. FIG. 6 shows an embodiment that is similar to that of FIG. 5 , butinstead with tension member 30 extending through a pair of eyelets 35,supported on the retaining element 18. As well as showing a slightlydifferent embodiment, FIG. 6 also shows imaging head 20 retracted andneedle 60 extending through aperture 40, as it would be in order to takea biopsy. Notably, in this position the needle would be within the fieldof view of ultrasound array 52. In embodiments, tension member 30 canpull head 20 into an obtuse angle, relative to the distal end of theendoscope 12. Generally, aperture 40 is in the shape of a long oval, sothat the needle 60 can pass through it over a long range of degree ofbending of neck 38. In another preferred embodiment, the flexibleconduit is extended distally from lumen 34 into a v-shaped indentation(not shown) on surface of flexible neck 38, aligning the conduit so thatthe needle 60 is aligned to pass through aperture 40.

To use imaging assembly 10, ultrasound assembly 14 is attached toendoscope 12 by means of retaining element 18. In an alternativeembodiment, rubber bands or clips 16 (FIG. 1 ) retain cable 22 to theside of endoscope 12. Imaging head 20 is then delivered to an area ofinterest, by means of standard endoscope introduction techniques.Imaging head 20 may then be moved to gain imagery of the area ofinterest by dedicated controls which control the ultrasound imaging head20 deflection. If there appears to be a finding to be sampled, needle 60may be introduced through an endoscope lumen and through aperture 40 andused to take a biopsy, inject a drug, or otherwise effect a medicalprocedure. Finally, needle 60 is retracted through the lumen ofendoscope 12 and the endoscope is retrieved from the patient's body. Inother embodiments, needle 60 is not included and an assembly that issimilar to imaging assembly 10 but without needle 60 and relatedelements, is used for imaging alone, or for introduction of some otherdevice.

FIGS. 7-13 show an alternative embodiment 70 of the assembly 10, withthe further innovation of a disposable head-movement sub-assembly 72,which includes a head clip 74, a movement cable 76, a cable clip 78 anda conduit 80, holding the major portion of movement cable 76. Aclip-hold 84 is defined on the back of imaging head 20′. Further, thecable clip 78 holds imaging head and other portions of the ultrasoundassembly 14′, including communicative cable 22′, to the endoscope 12.FIGS. 9-12 show engagement of head clip 74 to clip-hold 84. FIG. 9 showshead clip 74 distal to and being pulled back onto clip-hold 84, withFIG. 10 showing head clip 74 engaged to clip-hold 84 and FIGS. 11 and 12showing different sectional views of head clip 74 and clip-hold 84engaged together.

Another difference between assembly 70 and assembly 10 is the optionalpresence of a needle guide 90. FIG. 7 shows two additional variantneedle guides 90′ and 90″. In assembly 10 it is possible that a needle60 pushed out of a lumen of endoscope 12 could miss the aperture 40 inneck 38 and be blocked by neck 38 from further advancement. This mighthappen if a user attempted to push needle 60 into use when the neck 38was not sufficiently pulled back, to bring aperture 40 into the correctposition to let needle 60 pass through. The result could be damagecaused to imaging head 20′, cause by needle 60. A needle guide 90engages with aperture 40, so that needle 60 will be guided to aperture40 with certainty, or will be blocked by guide 90, when head 20′ is notpositioned correctly to align aperture 40 with the path of needle 60.FIG. 13 shows a needle guide 90 in use as head 20′ is pulled fully back,to a forward-looking position as needle 60 is advanced through aperture40, with the assistance of guide 90. It is a further advantage ofassembly 70 (and assembly 10) that the head 20′ can be moved to aforward-looking position as shown in FIG. 13 , which is helpful tosurgeons for some types of procedures. Referring to FIGS. 14 and 15 , ina variant 70′ to assembly 70, a needle guide 92 is provided in the formof a wire that needle 60 advances over. When not in use, needle guide 92is retained in a needle-guide notch 94 (FIG. 15 ).

Referring now to FIGS. 16-18 , a duodenoscope assembly 110 includes aduodenoscope 111 having a single-use instrument guidance head 112 (shownmost clearly in FIG. 18 ), having an instrument guide 114 extendingoutwardly at an angle between a first lateral direction L and the distaldirection P. Guidance head 112 can change the direction of guide 114, inresponse to varying user input via a tension member and an instrumentvariable guide member (not shown). Referring to FIG. 16 , a cable/headsub-assembly 120 includes an ultrasound imaging head 122, a scope clip124, a multiple signal pathway cable 126, delivering signals to imaginghead 122 and relaying signals from imaging head 122. The signal pathwaysof cable 126 may be electrical conductors, and more specifically mayeach be a coax cable or a trace on a flex circuit. Other forms of signalpathways are possible. Imaging head 122 is shown having a signalemission surface facing the first lateral direction L, and a clip-hold128 (FIG. 17 ) is present on head 122 on a side displaced from saidsignal emission surface in a second lateral direction, opposed to saidfirst lateral direction L. An imaging head movement sub-assembly 140includes a head clip 142, shaped to engage to clip-hold 128, a movementcable 144 a cable clip 146 and a conduit 148, holding the major portionof movement cable 144. Referring to FIG. 18 when cable 144 is pulled itpulls back imaging head 122 as indicated by the dotted line. In someembodiments sub-assembly 140 further includes an actuator (not shown) atthe proximal end, to permit an operator to draw in cable 144, therebypulling on imaging head 122 or let out cable 144, either pushing onimaging head 122 or permitting the resiliency of the material of cable126 to place head 122 into a position more aligned with the longitudinaldimension of the duodenoscope 111, at its distal end. The actuator ofcable 144 may take the form of a wheel, a lever or any other arrangementconvenient to the user.

Because disinfection techniques typically require the application ofchemicals in liquid form, thin crevices, into which liquid might noteasily flow are generally undesirable. Accordingly, clip-hold 128 isdesigned so as not to define thin crevices with the imaging head 122. Inalternative preferred embodiments, clip-hold 128 may have a shape thatis similar to a knob, to further avoid defining any narrow crevices.

As noted in the background, the disinfection of devices such as assembly110 is a matter of great concern, as there have been cases of the spreadof strains of bacteria that are resistant to multiple antibiotics, byway of duodenoscope reuse. One area which may prove particularlydifficult to sterilize is conduit 148, as movement cable 144 will tendto introduce body fluids into conduit 148 as cable 144 is pulled backinto conduit 148, as imaging head 122 is moved back. To address thisissue head movement sub-assembly is releasable and removable from theremainder of assembly 110 and is made to be inexpensive enough to use asingle time and then be disposed. This eliminates the possibility ofinfection being spread from patient to patient by way of sub-assembly140. Cable/head sub-assembly 120 does not have a similar structure thatwould provide a hard-to-reach place that would make disinfectiondifficult and will tend to be more expensive as it must contain amultiplicity of fine wires or other forms of signal pathways.Accordingly, cable/head sub-assembly 120 is designed to be cleaned andreused.

Before performing an endoscopic (duodenoscopic) procedure theendoscopist would obtain an unused head movement sub-assembly 140 andattach it to the remainder of assembly 110. After use, the user detachesand disposes sub-assembly 140.

Referring to FIG. 16 , movement cable 144 may be pulled back to causehead 122 to face in a more distal facing direction. Pushing cable 144forward causes head 122 to adopt a lateral viewing angle as shown, inone embodiment due to resilience of neck 150, but in another due tostiffness and compressive strength in cable 144.

Referring to FIGS. 19 and 20 , in an alternative preferred embodiment ofa duodenoscope assembly 210, a holder 224 encompasses together both theduodenoscope 211, the cable/head sub-assembly 220 and the imaging headmovement sub-assembly 240. A clip 225 also helps to hold the elementstogether.

In an additional set of embodiments and methods of use, any one ofassembly 14 (combined with tension member 30), and assembly 70 and thecombination of assemblies 120 and 140, can be made so that the resultantassembly 14/30, 70 or 120/140 (henceforth collective designated asassembly 14′) is produced and sold with a recommended method of use todispose the entire assembly after a single use. This may greatlysimplify health facility operations. In a preferred embodiment, theultrasound array 52 (or the array in imaging head 20′ or 122) is acapacitive micromachined ultrasonic transducer (CMUT), which isgenerally less expensive than a piezoelectric transducer. Becausecleansing an ultrasound assembly 14′ can be so cumbersome and expensive,and because of the great value of the surgeries being performed, even anassembly 14′ selling for upwards of $2,000 in 2019, could be moreeconomical to dispose of, than to be cleansed and reused. In oneembodiment of an assembly 14′, the number of array elements is reduced,from for example 256, to for example 128, or even to 64, to reduce thecost of the array, and the signal pathways leading to and from thearray.

While a number of exemplary aspects and embodiments have been discussedabove, those possessed of skill in the art will recognize certainmodifications, permutations, additions and sub-combinations thereof. Itis therefore intended that the following appended claims and claimshereafter introduced are interpreted to include all such modifications,permutations, additions and sub-combinations as are within their truespirit and scope.

1.-10. (canceled)
 11. An endoscope add-on assembly adapted to beattached to a target endoscope that defines a lateral axis and a distalaxis, the endoscope add-on assembly including: a) a scope clipconfigured to secure the endoscope add-on assembly to the targetendoscope; b) an ultrasound imaging sub-assembly configured toselectively engage an ultrasound imaging head; and c) an instrumentguide configured to change direction relative to the target endoscope inresponse to a varying user input.
 12. The endoscope add-on assembly ofclaim 11, wherein the instrument guide extends outwardly at an anglebetween the lateral axis and the distal axis.
 13. The endoscope add-onassembly of claim 12, wherein the instrument guide extends outwardly atan angle between the lateral axis and the distal axis at rest, andwherein the instrument guide extends outwardly at a second angle betweenthe lateral axis and the distal axis under a stress applied via thevarying user input.
 14. The endoscope add-on assembly of claim 11,wherein the ultrasound imaging sub-assembly comprises a clip configuredto secure the ultrasound imaging head to the ultrasound imagingsub-assembly.
 15. The endoscope add-on assembly of claim 14, wherein theultrasound imaging head comprises a signal emission surface on a side ofthe ultrasound imaging head opposed to the clip.
 16. The endoscopeadd-on assembly of claim 15, wherein the signal emission surface facesthe target endoscope.
 17. The endoscope add-on assembly of claim 16,wherein the clip faces away from the target endoscope.
 18. The endoscopeadd-on assembly of claim 11, wherein the varying user input is providedvia a member comprising a compressive strength.
 19. The endoscope add-onassembly of claim 18, wherein the member is configured to traversethrough a lumen of the target endoscope.
 20. The endoscope add-onassembly of claim 11, wherein the varying user input is provided via aninstrument variable guide member.
 21. The endoscope add-on assembly ofclaim 11, wherein the varying user input is provided via a tensionmember.
 22. The endoscope add-on assembly of claim 21, wherein thetension member comprises a wire.
 23. An endoscope add-on assemblyadapted to be attached to a target endoscope, the endoscope add-onassembly including: a) an ultrasound imaging head; b) an ultrasoundimaging sub-assembly configured to selectively engage the ultrasoundimaging head, wherein said ultrasound imaging sub-assembly comprises ascope clip configured to secure the ultrasound imaging sub-assembly tothe target endoscope; and c) an instrument guide configured to changedirection relative to the target endoscope in response to a varying userinput provided via a member comprising a compressive strength.
 24. Theendoscope add-on assembly of claim 23, wherein the target endoscopedefines a lateral axis and a distal axis, and wherein the instrumentguide extends outwardly at an angle between the lateral axis and thedistal axis.
 25. The endoscope add-on assembly of claim 24, wherein theinstrument guide extends outwardly at an angle between the lateral axisand the distal axis at rest, and wherein the instrument guide extendsoutwardly at a second angle between the lateral axis and the distal axisunder a stress applied via the varying user input.
 26. The endoscopeadd-on assembly of claim 25, wherein the ultrasound imaging headcomprises a signal emission surface that faces the target endoscope. 27.The endoscope add-on assembly of claim 23, wherein the member comprisesa tension member.
 28. The endoscope add-on assembly of claim 27, whereinthe tension member comprises a wire.
 29. An endoscope add-on assemblyadapted to be attached to a target endoscope, the endoscope add-onassembly including: a) an ultrasound imaging head; b) an ultrasoundimaging sub-assembly configured to selectively engage the ultrasoundimaging head, wherein said ultrasound imaging sub-assembly comprises ascope clip configured to secure the ultrasound imaging sub-assembly tothe target endoscope; and c) a needle guide assembly configured todirect a motion of a needle of the target endoscope, wherein the needleguide further comprises a needle guide notch.
 30. A method of using anendoscope add-on assembly, the method comprising: securing an ultrasoundimaging sub-assembly of the endoscope add-on assembly to a targetendoscope via a scope clip of the ultrasound imaging sub-assembly;selectively engaging an ultrasound imaging head to the ultrasoundimaging sub-assembly of the endoscope add-on assembly via a clip; andproviding a varying user input to an instrument guide of the endoscopeadd-on assembly via a member comprising a compressive strength, whereinthe instrument guide of the endoscope add-on assembly is configured tochange direction relative to the target endoscope in response to avarying user input.
 31. The method of claim 30, further comprising:removing the ultrasound imaging head from the ultrasound imagingsub-assembly of the endoscope add-on assembly after use; and cleaningthe ultrasound imaging head for reuse via the endoscope add-on assembly.